tbuckley/cabot-search huggingface dataset:
Abstract P3196: Voluntary Exercise Training Does Not Prevent High Phosphate Diet-induced Mitochondrial Dysfunction
Authors: Hannah F Sanders, Daniel A Branch, Luke J Pepperney, Jooho Oh, Camille E Zonfa, Rose Liu, Rafia A Baig, Molly K Sheridan, Kedryn K Baskin
Journal: Circulation Research (2023)

Inorganic phosphate (Pi) is used extensively as a preservative and a flavor enhancer in processed foods consumed as part of a Western diet. Mice fed high-Pi diet (HP) for 12 weeks display decreased maximal exercise capacity but no change in cardiac function. Expression of fatty acid metabolism genes are decreased and expression of glucose metabolism genes are increased in skeletal muscle after HP diet. Consequently, mitochondrial function is significantly impaired in skeletal muscle from mice fed HP diet. In the current study we test the hypothesis that voluntary exercise training prevents the negative metabolic consequences of HP diet. We housed mice in voluntary wheel running cages and fed them a normal-Pi (NP) or HP diet. HP diet did not alter body weight or composition, and NP- and HP-fed mice voluntarily ran the same distance in wheel cages throughout the study. Using incline treadmill exercise tolerance tests we observed no differences in medium-intensity exercise capacity between NP- and HP-fed mice subjected to voluntary wheel running, contrary to findings in sedentary mice. Despite preserved exercise capacity, muscle mitochondrial function in mice fed HP diet was significantly decreased after 5 weeks, which continued to decline after 12 weeks of HP diet and voluntary exercise. To investigate mechanisms of HP-induced mitochondrial dysfunction we measured expression of key metabolic genes and found that fatty acid metabolism genes were significantly decreased in muscle from mice fed HP diet and subjected to voluntary exercise. These data suggest that voluntary exercise training does not prevent the negative metabolic consequences of consuming a high-phosphate diet. Thus, dietary Pi may represent a novel and modifiable target to reduce physical inactivity associated with the Western diet.
Abstract P2086: Targeting Endothelial Dysfunction And Senescence An Heart Failure With Preserved Ejection Fraction - A Whole Transcriptome Analysis Of Heart Failure With Preserved Ejection Fraction-patients To Identify New Therapeutic Targets
Authors: Leonie Wurmbrand, Katrin Kalies, Kai Knoepp, Jochen Dutzmann, Daniel SEDDING
Journal: Circulation Research (2023)

Heart failure with preserved ejection fraction (HFpEF) remains a disease with a poor prognosis and increasing incidence in all Western countries mainly affecting the aging population. A deeper understanding of pathogenesis at the cellular level, particularly the central role of endothelial dysfunction in cellular senescence, is required for the development of new therapeutic approaches. Circulating endothelial cells as a marker for endothelial damage and dysfunction, have already been examined quantitatively in general HF patients, HFpEF patients and healthy subjects. Here, we aim to isolate circulating endothelial cells to target endothelial dysfunction and identify new therapeutic targets by whole transcriptome analysis.Methods included the isolation of circulating endothelial cells (CEC) from whole blood samples via a newly established FACS panel. HFpEF patients were included based on their HFA-PEFF score. Young and old subjects served as non-diseased controls and were matched as closely as possible for sex and age. CEC were further processed for a whole transcriptome analysis. In total, we collected samples from n=15 patients per group. Mean age was 82.3 for the HFpEF group, 64.5 for the non-diseased control ‘old’, and 25 years for the non- diseased control ‘young’, HFA-PEFF score was 5, 0, and 0 points (P&lt;0.05), and the proportion of female patients was 66%, 78%, and 77%, respectively. Including additional patient data, our collective was shown to be comparable to large HFpEF studies and clinical registries. CEC cells were sorted based on CD45-, CD11b- CD34+, CD31+ and CD146+ marker expression. The CEC of the aged group revealed upregulated expression of senescence markers p16, p21 and CD44. In gene set enrichment analysis, we see trends of differentiation of mainly proliferation- and transcription-associated gene sets in heart failure with preserved ejection fraction. In summary, we achieved to isolate CEC from whole blood of HFpEF-patients and matched controls. The whole transcriptome analyses may provide new clues for therapeutic strategies, which is now the subject of further in vitro and in vivo studies. Our goal is to develop new therapeutic targets after successful evaluation and modulation of the target genes.
Abstract P2091: Histone Deacetylase 6 (HDAC6) Inhibitor Improves Stress-Induced Cardiomyocyte Restructuring in Heart Failure with Preserved Ejection Fraction (HFpEF) in a Multimodal Manner Based on Single Nucleus RNA-seq (snRNA-seq) Analyses
Authors: Farshad Farshidfar, Matthew Kozubov, Reva Shenwai, Amir Hosseinian, Jin Yang, Aliya Zeng, Iris Wu, Amara Greer-Short, Charles Mackay, James Priest, Timothy Hoey
Journal: Circulation Research (2023)

In the high fat diet (HFD)/L-NAME mouse model of HFpEF, Ranjbarvaziri et al from Tenaya Therapeutics have previously shown that pharmacological inhibition of HDAC6 improves functional and structural cardiac metrics, together with improved oxidative phosphorylation, improved contraction, and reduced fibrosis. Tissue level as well as single cell level transcriptional studies of control, HFD + L-NAME HFpEF, and HFD + L-NAME HFpEF treated with either HDAC6 inhibitor TYA-018 or SGLT2 inhibitor empagliflozin, demonstrated extensive reversal of disease phenotypes in mice treated with TYA-018. Based on snRNA-Seq analyses, we report characterization of cardiomyocyte (CM) subtypes in HFpEF that establish specific and substantial cell-cell interactions with their surrounding fibroblasts and endothelial cells. These interactions initiate CM-subtype-specific signaling cascades, leading to emergence of ‘stressed’ hypoxic CM and hypercontractile CM subtypes. We show that these cell types increase in the HFpEF disease state. The proportion of ‘stressed’ CMs at tissue level corresponds to the worsening cardiac functional measures, and their composing fractions in left ventricle tissue decline and normalize after TYA-018 treatment. These findings suggest HDAC6 inhibition may regulate undesirable HFpEF phenotype characteristics such as dysregulated metabolism, fibrosis and hypertrophy, and also present detailed cell-level evidence of HDAC6 inhibition’s favorable effects in metabolic syndrome.
Abstract P2076: Disrupting Nicotinamide Nucleotide Transhydrogenase Prevents Cardiometabolic Heart Failure With Preserved Ejection In Mice.
Authors: Mark E Pepin, Philipp Konrad, Sumra Nazir, Matthias Dewenter, Johannes Backs
Journal: Circulation Research (2023)

Heart failure with preserved ejection fraction (HFpEF) represents a common clinical endpoint of cardiometabolic diseases which impair myocardial diastolic relaxation and/or stiffness. Although myocardial redox perturbations are known to accompany HFpEF, their contribution to its pathogenesis has not been clearly demonstrated. Therefore, our multi-cohort murine study sought to determine whether constitutive expression of NNT, a mitochondrial transhydrogenase that couples NADPH:NADP + to NADH:NAD + homeostasis, is required for the cardiometabolic manifestations of HFpEF in mice. Four cohorts of 12-week-old male and female mice with wild-type (NNT +/+ ) or mutant (NNT -/- ) NNT were supplied a combined high-fat and 0.5% N(ω)-nitro-L-arginine methyl ester (HFD-LNAME) diet for 9 weeks (n = 6-10). Although male NNT +/+ mice developed expected increases in body weight (23.2% Δ, P = 0.003), hypertension (24 ± 5 Δ mmHg, P = 0.02), impaired glucose tolerance ( P = 0.006), and reduced maximal treadmill running distance (-172 ± 73.1 Δ m, P = 0.006) following 9 weeks HFD-LNAME, male NNT -/- mice were protected against such cardiometabolic dysfunction. As previously shown, female mice failed to develop cardiometabolic dysfunction independent of NNT genotype. Cardiac phenotyping via echocardiography and invasive PV-loop analysis revealed increased E/e’ (42.8 vs. 21.5, P &lt; 0.001) and E/A (2.3 vs 1.4, P = 0.007) ratios, diastolic stiffness (0.09 vs 0.04 mmHg/μL, P = 0.02), and myocardial fibrosis ( P = 0.02). Myocardial transcriptomic analysis via RNA-sequencing revealed robust unsupervised clustering of both genotypic and dietary groups, which ultimately showed disproportionate perturbations mitochondrial metabolic and redox signaling intermediate genes. Our search for putative transcriptional regulators identified NAD + deacetylase Sirt3 as an NNT-dependent oxidative response gene that appears to underlie cardiometabolic HFpEF. Taken together, these observations support that the loss of NNT protects against nitrosative stress-induced cardiac and metabolic consequences of HFD-LNAME in mice, thus highlighting a novel therapeutic avenue for HFpEF.
Abstract EC.10: Transcriptional Heterogeneity Of The Postnatal Cardiac Conduction System
Authors: Yena Oh, Rimshah Abid, Saif Dababneh, David Cook, Jin Park, Barbara Vanderhyden, Nikhil Munshi, Kyoung-Han Kim
Journal: Circulation Research (2023)

The cardiac conduction system (CCS) is a network of specialized cardiomyocytes responsible for the coordinated spreading of electrical impulses throughout the heart for synchronized contractions. The CCS is largely made up of the sinoatrial node (SAN), atrioventricular node (AVN) and the fast-conducting ventricular conduction system (VCS), which is further divided into the His bundle, Bundle branches and Purkinje fibers. Although these CCS structures were anatomically discovered &gt;100 years ago, their molecular constituents are not fully known. In this study, CCS cells, making up ~0.05% of myocytes (~500 cells/heart), were isolated from early postnatal hearts (postnatal day 1 to 4) of fluorescent reporter mice (Cntn2-Cre;Rosa26TdTomato), purified using fluorescence-activated cell sorting, and subjected to single-cell RNA-sequencing. Unbiased cluster analysis on ~7000 CCS cells demonstrated distinct transcriptomic profiles in the SAN, AVN, proximal VCS ( His bundle, bundle branches) and distal VCS ( Purkinje fibers). Conforming to previous studies, global conduction markers, such as Cntn2 and Id2, were present throughout the entire CCS, while a VCS-specific transcription factor, Irx3 , was expressed only in the VCS. A comparison between proximal and distal VCS components revealed enrichments of Igfbp7 , Lyz2 and Sfrp5 in the proximal VCS, and Scn10a , Psd3 and Wisp1 in the distal VCS. Sub-clustering analysis followed by validation with immunostaining further identified unique molecular profiles of the SAN ( Shox2 , Vsnl1 ), AVN ( Rspo3 ), His bundle ( S100a6 , Pcp4 ) and bundle branches ( Nppa , Mest ). Data integrating publicly available ATAC-seq in SAN, AV junction, and atrial and ventricular cardiomyocytes as well as Tbx3-ChIP-seq, suggested that these regional markers are possibly regulated by two CCS-specific transcription factors, Irx3 and Tbx3 . More importantly, overexpressing Irx3 and/or Tbx3 in cultured neonatal mouse atrial and ventricular myocytes recapitulated these region-specific expression patterns in a dish. Together, our study provides a comprehensive view of the molecular profiles within the postnatal CCS at a high-resolution and show Irx3 and Tbx3 as genetic regulators establishing heterogeneities of the CCS.
Abstract P2083: Heart Failure With Preserved Ejection Fraction Mouse Model Development With Aav-renin
Authors: Yuji Shi
Journal: Circulation Research (2023)

Heart failure with preserved ejection fraction (HFpEF) accounts for more than half of heart failure patients, with limited approved evidence-based therapies. HFpEF is a complex multifactorial disease associated with comorbidities of hypertension, obesity, diabetes, and renal dysfunction. While the pathophysiology of HFpEF has yet to be fully understood, the development of therapies is hindered partially by limited choices of translationally relevant preclinical models that recapitulate human HFpEF clinical features. Here, we report the development of mouse models of HFpEF through a combination of metabolic and hypertensive stress mediated through activation of the renin-angiotensin-aldosterone system (RAAS) via AAV-Renin. These novel mouse models demonstrate clinically relevant features of human HFpEF, including preserved ejection fraction (EF), concentric cardiac hypertrophy, left atrial enlargement, diastolic dysfunction, elevated natriuretic peptides, inflammation, and exercise intolerance. We also demonstrate that approved HFpEF therapies valsartan/sacubitril (Entresto) and Empagliflozin effectively improve the cardiac phenotypes of HFpEF in this model. In summary, we have established two novel two-hit mouse HFpEF models by combing hypertension induced by AAV-Renin and metabolic stress caused by either HFD or a novel mouse strain with metabolic syndrome. These models faithfully represent the cardiometabolic HFpEF phenogroup and will provide new tools for HFpEF preclinical research and drug discovery.
Abstract P3090: The Role Of Circular Cdr1as In Macrophage Cardiac Inflammation And Fibrosis
Authors: Carolina Gonzalez, Maria Cimini, Cindy Benedict, Vandana Mallaredy, May Trungcao, Sudarsan Rajan, Venkata N Garikipati, Raj Kishore
Journal: Circulation Research (2023)

In response to cardiac injury, macrophages are recruited in high numbers to the infarcted myocardium and undergo phenotypic switching from pro-inflammatory in the early stage to anti-inflammatory in the later stage. Thereby, controlling the initiation, maintenance, and resolution of the inflammatory response. Circular RNAs are newly discovered non-coding RNA generated from protein-coding genes that implicated in the regulation of immune cells. However, there are currently no reports on the role of circRNAs in macrophage biology and function during cardiac ischemia. We aim to determine the specific role of circ-CDR1as in macrophage class switching and how circ-CDR1as modulates function post-cardiac injury. We performed circular RNA microarray analyses to assess circRNA transcriptome changes using RNA isolated from bone marrow derived macrophages (BMDM) polarized to a M1 or M2 phenotype. We validated circRNA expression by RT-qPCR in 3D post-MI hearts and within specific cell types. We generated circCdr1as overexpression plasmid transfected into BMDM, changes in phenotype were determined by FACS and RT-qPCR analysis. We generated circ-CDR1as overexpression associated adenoviral vector plasmid under control of CMV promoter and administered by tail vein injection. LV function was determined by echocardiography. Macrophage phenotype and CD31 was determined by immunohistochemistry and fibrosis by masson trichrome staining. Circ-CDR1as is downregulated in M1 macrophages and upregulated in M2 macrophages. There is a downregulation of cdr1as in cardiomyocytes and macrophages (F4/80+) 3 days post MI, during which pro-inflammatory macrophages are dominant. Administration of AAV9 circCDR1as in vivo significantly improved %EF and %FS at 21 and 28D days post-MI. Masson trichrome staining showed significant decrease in fibrotic area. Additionally, there is an increase in CD206+ cells at the border zone/infarcted area. This study suggests that circ-Cdr1as plays a role in macrophage biology by upregulating anti-inflammatory markers to promote an M2 phenotype and exogenous gene delivery of circCDR1as may improve LV function over time. Therefore, circ-Cdr1as may potentially be a therapeutic for the resolution of inflammation after cardiac injury.
Abstract P3072: Effects Of Antiviral Innate Immune Activation On Cytokine Secretion And Function Of Human Ipsc-derived Cardiomyocytes
Authors: Deepthi Ashok, Ting Liu, Meghana Prakash, Jason Kim, Bryan Ho, Kyriakos Papanicolaou, Deok-Ho Kim, Brian O'Rourke
Journal: Circulation Research (2023)

Introduction: Acute and long-term cardiovascular complications of COVID-19 have been reported, ranging from arrhythmias, ischemic heart disease, and heart failure to cerebrovascular and cardiometabolic disorders, yet the underlying molecular mechanisms are not well understood. Here, we examine the effects of stimulating the double-stranded RNA (dsRNA) pattern recognition receptor pathway, which is strongly induced to activate interferon-stimulated gene (ISG) expression in the heart during COVID-19, on excitation-contraction coupling and mitochondrial function. While providing antiviral protection, we hypothesize that, even in the absence of cardiac viral replication, this pathway might contribute to COVID-19-related cardiac dysfunction. Results: We used the viral dsRNA mimetic polyinosinic: polycytidylic (PIC) to induce a type I interferon response in iPSC-CM or A549 (lung epithelial) cells. In iPSC-CM, PIC induced robust protein expression of STAT1/pSTAT1, OAS2, OAS3, IRF7, pIRF7, IRF9 and MX1. A marked increase in cytokine protein secretion was also observed, with significant increases in CXCL-10 (~160 fold), IL6, CCL5 (~20-fold) IL8 (15-fold), and CXCL1 (~10-fold), and a 2-5-fold increase in ~30 other cytokines. Negative effects on excitation-contraction coupling were observed after 72 hours of PIC treatment, manifested as a 25% reduction in iPSC-CM Ca2+ transient amplitude. Microelectrode array analysis of iPSC-CM monolayers revealed electrophysiological dysfunction: PIC treatment increased cardiac field potential duration and spike amplitude, but reduced beat periods. A549 cells also showed increases in interferon pathway genes (STAT1, pSTAT1, IRF3, pIRF3, OAS1,2,3 and IFNb1), along with increased rates of RNA degradation after PIC treatment, consistent with activation of the OAS/RNAseL dsRNA sensor pathway. PIC-treated A549 cells also showed a large decrease in oxidative phosphorylation (maximal respiration and spare respiratory capacity), which was prevented by the mitochondrial antioxidant, mitoTEMPO. Conclusions: Activation of the viral dsRNA innate immune sensor pathway, even in the absence of active cardiac viral replication, might contribute to mitochondrial and cardiac dysfunction in COVID-19.
Abstract P3054: Further Delineation And Exploration Of The Cardiac MicroRNA-Target Interactome
Authors: Bailey Peck, Jared M McLendon, Ryan L Boudreau
Journal: Circulation Research (2023)

MicroRNAs (miRs) have emerged as key players in cardiac biology and disease. These non-coding RNAs are loaded into Argonaute (Ago) proteins to direct suppression of target mRNAs via base-pairing. Despite a mass of research on cardiac miRs in model systems and humans, the translational impacts have been limited since miR-mRNA target interactions in heart tissues have not been adequately defined at the “-omics” level. Researchers heavily rely on predicted miR targets and are often misled by false predictions, since imperfect base-pairing is sufficient for miR binding. Our goal is to comprehensively define miR targeting events and their biological relevance in the heart and to understand the clinical significance of genetic variants (e.g. SNPs) that modulate cardiac miR functions. We previously used high-throughput biochemical means (Ago2 CLIP-seq) to generate the first transcriptome-wide map of miR binding sites in non-failing human hearts, yielding ~4000 sites across &gt;2000 genes. While exploring this dataset, we discovered translationally relevant miR-SNP interactions that associate with heart failure patient outcomes, most notably in SCN5A . We have since identified multiple common missense variants in TTN that disrupt miR binding. These associate with heart structure/function measures in the general population and could have significant implications for cardiomyopathy patients with TTN mutations. Beyond SNPs, we made the surprising discovery that TTN mRNA harbors &gt;20 miR-133 binding sites and has the potential to bind up to 20% of the miR-133 pool in cardiomyocytes, perhaps serving as an endogenous miR “sponge”. We experimentally validated the potential for this using a TTN mini-gene harboring 18 of the most strongly bound miR-133 target sites; we found that this construct was capable of inhibiting miR-133 activity in cells. Finally, to further expand these studies, we optimized our protocol by adapting state-of-the-art CLIP methods, which recently yielded our 2 nd generation map of human cardiac miR binding sites (now in failing hearts), leading to the identification of &gt;12,000 bindings sites across &gt;6000 genes. We are now interrogating these data and processing additional samples to investigate how miR binding profiles rewire in failing hearts.
Abstract P2038: Role Of The Microtubule Network In Right Ventricle Passive Viscoelasticity With Pulmonary Hypertension Development
Authors: Kristen LeBar, Adam J Chicco, Zhijie Wang
Journal: Circulation Research (2023)

Microtubule (MT) polymerization is a key contributor to myocardium viscoelasticity, which describes elastic and viscous resistance under stress and impacts the contractile function. MT de- or hyper-polymerization has been shown to decrease or increase healthy cardiomyocyte viscoelasticity, but the responses of hypertrophied cells to these modifications are unknown. Moreover, the ventricular free wall is a complex tissue composed of myofibers, collagen and vasculature, and it exhibits anisotropic mechanical behavior. To fully understand the role of MT in the tissue-level anisotropic viscoelasticity of myocardium, we investigated the responses of healthy and failing rat right ventricles (RV) to alterations in MT network. All procedures were approved by Colorado State University IACUC. Adult male rats were treated with monocrotaline to induce pulmonary hypertension and RV failure. After euthanasia, the RV free wall underwent equibiaxial stress relaxation in intact state (baseline) and under the treatment of colchicine and deuterium oxide (D 2 O) to remove and enhance MT network, respectively. Viscoelastic parameters were quantified as previously described. As expected, the diseased RV had greater viscoelasticity than the healthy RV. Depolymerization of MT in healthy RVs reduced tissue viscosity (relaxation rate) and elasticity (relaxation modulus), and the changes were more significant in the longitudinal (outflow tract) direction. MT hyper-polymerization increased tissue elasticity and decreased viscosity, with the changes stronger in the circumferential direction. In diseased RVs, MT depolymerization reduced viscosity in both directions and elasticity only in the circumferential direction. However, MT hyper-polymerization unexpectedly decreased tissue elasticity and tended to decrease viscosity, as well. The altered MT polymerization dynamics after D 2 O treatment in a fibrotic environment may explain these heterogeneous responses This is the first report of distinct impacts of MT polymerization on the tissue mechanical behavior between the hypertrophied and healthy myocardium. The exact molecular mechanisms involving MT polymerization dynamics and the interactions with collagen await further investigation.